In the packaging and other similar industries where it is desired to pick up (in the idiom of the industry “pick”) a unit, for example a loaf of bread, a manufactured part or assembly etc., vacuum assisted suction devices are commonly used. Such devices generally and commonly comprise a large vacuum plenum with many vacuum assisted suction cups, i.e. cup shaped devices to which a vacuum is applied from the interior of the plenum, attached thereto. With such an arrangement, there is always a loss of vacuum from through any suction cup that does not engage a product being picked. If the object or objects being picked do not cover all of the vacuum assisted suction cups from a single plenum, then leakage due to the uncovered suction cups will cause a reduction of the vacuum inside of the plenum and the object or objects that are to be picked may not be exposed to adequate vacuum to permit their picking. Thus, problems arise when the objects to be picked do not cover all of the suction cups or when multiple products need to be lifted by a single plenum having a multitude of suction cups.
Several methods have been suggested to solve this problem. The traditional method is to section off the plenum or end effector into multiple chambers each with its own individual vacuum source. Objects can then be picked one at a time since each of the products or objects can be lifted by a vacuum produced by its own discrete “plenum”. An alternative conventional solution to solve this problem where all but a few suction cups are covered by the object to be picked is to increase the vacuum level to compensate for leakage.
As is apparent to the skilled artisan, when the foregoing solution of “chambering” the vacuum plenum to accept a particular vacuum assisted suction cup configuration for a particular product or set of products is implemented, a product change inevitably requires a plenum chambering reconfiguration to insure proper picking of the newly introduced product or product array. Such a reconfiguration is time consuming and expensive in terms of manpower and downtime.
From the foregoing, it is apparent that there currently exists a problem with the ability of conventionally designed vacuum assisted suction cup picking systems as it relates to their ability to accept product configurations that either do not cover all of the suction cups of a particular suction cup configuration, or to adapt to product handling changes.